customize GRR3

Hi. I have a huge problem. In my company there are 4 business units (BUKRS). At this moment there is one setting of costs-structure in GRR3 for all business units. My task is to allow different customizing for one of units in that way the structure won't influence on other units reports ( reports from GRR3 -> 1VK / "Cost Centers: Absorption Costing VAI").

Is there some possibility to customize that? Or maybe I have to write a separate new transaction which'll give user reports? Can You give me some tip? Greetings. P.|